It has been reported that a Bank of Ireland laptop with thousands of customers' details was stolen seven years ago in Co Kildare and that clients were not told of the theft.
"Bank of Ireland is investigating an allegation of a stolen laptop computer dating back to 2001,” a bank spokesman said.
“The bank would like to reassure customers that the risk level of any data from seven years ago being used for fraudulent purposes is extremely remote."
Bank of Ireland is facing other investigations in the wake of the revelation that laptops with details of 100,000 customers were stolen last year.
The four laptops belonging to Bank of Ireland Life were stolen from different staff members between June and October last year, but the data protection commissioner and financial regulator were only told recently.
None of the stolen information was encrypted, although lesser forms of security, such as password protection, were in place.